Table 4 Univariate analysis of the POS among three classes (N = 305)

Age, years, n (%)

15.770

< 0.001

 < 65

87 (61.3)

38 (26.8)

17 (12.0)

 ≥ 65

67 (41.1)

51 (31.3)

45 (27.6)

Gender, n (%)

5.239

0.073

 Male

106 (55.2)

53 (27.6)

33 (17.2)

 Female

48 (42.5)

36 (31.9)

29 (25.7)

Education level, n (%)

14.020

0.007

 Junior high school and below

58 (40.6)

46 (32.2)

39 (27.3)

 Senior high school

48 (55.2)

24 (27.6)

15 (17.2)

 Senior high school above

48 (64.0)

19 (25.3)

8 (10.7)

Place of residence, n (%)

15.188

0.001

 Rural

3 (12.5)

13 (54.2)

8 (33.3)

 Urban

151 (53.7)

76 (27.0)

54 (19.2)

Marital status, n (%)

2.379

0.304

 Married

132 (52.4)

72 (28.6)

48 (19.0)

 Unmarried, divorced or widowed

22 (41.5)

17 (32.1)

14 (26.4)

Per capita monthly household income, n (%)

87.850

< 0.001

 < 2,000 Yuan RMB (approximately 280.4341 US$)

12 (13.2)

39 (42.9)

40 (44.0)

 2,000–5,000 Yuan RMB (approximately 280.4341–701.0853 US$)

61 (57.0)

33 (30.8)

13 (12.1)

 > 5,000 Yuan RMB (approximately 701.0853 US$)

81 (75.7)

17 (15.9)

9 (8.4)

Health insurance

 No

1 (17.0)

4 (66.7)

1 (17.0)

4.375

0.112

 Yes

153 (51.2)

85 (28.4)

61 (20.4)

Primary cause, n (%)

1.836

0.986

 Glomerulonephritis

42 (51.9)

23 (28.4)

16 (19.8)

 Diabetic nephropathy

37 (46.8)

24 (30.4)

18 (22.8)

 Hypertensive nephropathy

43 (51.8)

23 (27.7)

17 (20.5)

 Polycystic kidney/nephrotic syndrome

15 (53.6)

7 (25.0)

6 (21.4)

 unknown

17 (50.0)

12 (35.3)

5 (14.7)

Duration of MHD since diagnosis, years, n (%)

2.758

0.839

 < 2

32 (50.8)

17 (27.0)

14 (22.2)

 2–5

75 (49.7)

45 (29.8)

31 (20.5)

 5–10

25 (47.2)

19 (35.8)

9 (17.0)

 > 10

22 (57.9)

8 (21.1)

8 (21.1)

 Serum phosphorus (mmol/L), M (P₂₅, P₇₅)

1.83 (1.49, 2.22)

1.70 (1.38, 2.24)

1.56 (1.18, 2.04)

7.345

0.025

 Serum calcium (mmol/L), M (P₂₅, P₇₅)

2.27 (2.19, 2.42)

2.30 (2.12, 2.44)

2.27 (2.12, 2.40)

0.347

0.841

 Hemoglobin (g/L), M (P₂₅, P₇₅)

112.50 (102.0, 121.25)

109.0 (97.0, 119.0)

103.0 (91.0,116.5)

7.962

0.019

 Intact parathyroid hormone (pg/ml), M (P₂₅, P₇₅)

157.30 (86.05, 279.03)

181.70 (79.76, 311.05)

173.0 (110.13, 284.43)

1.192

0.551

 Clearance index of urea (Kt/V), M (P₂₅, P₇₅)

1.45 (1.32, 1.64)

1.47 (1.25, 1.67)

1.49 (1.25, 1.64)

0.007

0.996

 Overall symptom burden, Mean ± SD

12.27 ± 4.55

15.73 ± 4.11

20.45 ± 3.07

87.558

< 0.001

 Overall symptom severity, Mean ± SD

23.19 ± 9.10

32.88 ± 10.17

49.19 ± 10.0

163.662

< 0.001

 KPS, M (P₂₅, P₇₅)

90.0 (90.0, 90.0)

80.0 (60.0, 90.0)

60.0 (50.0, 70.0)

118.103

< 0.001

 PHQ-9, M (P₂₅, P₇₅)

4.0 (2.0, 6.0)

7.0 (5.0, 9.0)

13.0 (10.0, 15.0)

157.574

< 0.001

 SSRS, M (P₂₅, P₇₅)

35.0 (29.8, 42.0)

31.0 (27.0, 36.0)

26.0 (24.0, 28.0)

81.162

< 0.001